Applicator



Feb. 27, 1962 I R. w. RIDDELL APPLICATOR 2 Sheets-Sheet 2.

Filed Jan. 9, 1957 FIG7 FIVG l3 FIG l0 FIG l4 lwz z/vra/a ROBERT WR/DELL ilnited States Patent 3,022,955 APPLICATOR Robert W. Riddell,Evanstou, BL; Arthur G. Gilkes,

administrator of said Robert W. Riddeil, deceased, assignor to ElizabethWhite Riddeli, Buttaio, N. Y.

Filed Jan. 9, 1957, er. No. 633,246 4 Claims. (Cl. 239-456) My inventionrelates to pressure type applicators for fluent solids and pastesincluding a variety of industrial pastes such as solders, brazes,greases and the like. In a particular aspect, it provides apparatuscapable of operating with economy and efiiciency at high speed inproduction line work. In other aspects, it provides for such apparatus anovel applicator gun including a novel valve and ejection nozzle meanspermitting flexible operation for a variety of application requirementsunder a variety of operating conditions.

Numerous attempts have been made to design applicators for industrialpastes, e.g. solders, which are suitable for production line operationssuch as production line brazing and soldering. Conventionally designedapplicators, however, have been plagued with plugging and leakingdifiiculties and resulting erratic operation which have made themunsuitable for production work. Pressure type applicators have requiredexcessively high pressures for operation, that is higher than availablefor the usual plant air supply, which rarely exceeds about 100 p.s.i.g.Moreover, when the required high pressure air is supplied, pluggingproblems are accentuated. Operation at high pressure can causeseparation of solid and liquid components used in solders and brazes.The liquid carrier medium sprays from the applicator nozzle while themetal, or other solid particles in the paste, remains in the nozzlesystem, resulting in rapid plugging. The resuiting shutdown is costly,and maintenance and cleaning are difiicult.

In accordance with my invention, a pressure type applicator system isprovided which comprises a supply tank, a delivery tube and anapplicator gun. The applicator gun, the design of which represents aspecial aspect of the invention, includes a smooth bore barrelcontaining an inlet port at one end and an outlet at the other end. Avalve in the barrel is adapted to close the outlet so as to effectperiodic controlled discharge from it. The valve essentially consists ofa rod-likeelongated cylindrical closure member and a conical-facd seatopening into the outlet. The conical valve seat is characterized by anincluded angle not exceeding about 28. The outlet port defines a nozzleorifice which may be integrated into a variety of nozzle designs. Meansare provided for supplying liquid from the supply tank to the applicatorgun and for actuating the valve in a manner, whereby con trolleddischarge of the liquid through the nozzle orifice may be effected.

Several variants of the invention will be described in connection withthe accompanying drawings but other modifications of the invention willbe apparent to those skilled in the art. The drawings comprise 14figures of which:

FIGURE 1 is a sketch in somewhat simplified and schematic form of asectionalized View of a pressure type applicator of the invention.

FIGURE 2 is a view in section of the nozzle portion of the applicatorgun of FIGURE 1 illustrating the discharge position of the valve.

FIGURE 3 is an enlarged sketch of a valve closure member of a typeemployed in the applicator gun of FIGURE 1.

FIGURES 4, 5 and 6 are enlarged views in section of 3,ZZ,55 PatentedFeb. 27, 1962 the nozzle valve and orifice of FIGURE 1 in various stagesof operation.

FIGURES 7 and 8 are views in section of two different types of nozzlemembers.

FIGURES 9 and 10 are views in section of a modified nozzle member andadaptor therefor.

FIGURES l1, 12, 13 and 14 illustrate in respective sectional and planviews two types of discharge members adapted for use with the nozzlemember and adaptor of FIGURES 9 and 10.

Referring to FIGURE 1, the applicator system employs a pressure supplytank which is provided with a conical bottom 111. For the purpose of theinvention it is advantageous that the included angle of the conicalbottom should be less than about 45, preferably about 2036, and moreadvantageously about 25-30. As illustrated in the drawing the includedangle of the conical bottom is about 36". Supply tank 110 in the drawingis not drawn accurately to scale and only a single inlet pipe 112 isshown. It will be understood that air pres sure is applied, and chargepaste periodically is supplied through pipe 11.2, but that a separatefill pipe may be provided if desired to permit continuous orintermittent charging of paste to the tank. Means can be provided in thetank for agitation if such should be desired.

Outlet line 113 is centrally located in conical bottom 111 and makes aflush connection with delivery tube 114 by means of connector 115. It isadvantageous to avoid ledges or protuberances of any kind in the passagefrom conical bottom 111 through outlet pipe 113 to delivery tube 114 andindeed throughout the paste delivery system. Delivery tube 114 may beany type of flexible hose or tubing but advantageously is a smoothplastic tubing such as vinyl tubing, nylon, polyethylene, etc. Theplastic materials appear to be more suitable than rubber. Delivery tube114 is joined to applicator gun 15 at inlet 16 by means of threadedconnector 17.

Applicator gun 15 comprises barrel member 18, a nozzle member 19 and avalve actuating member 2%. Barrel member 18 contains a smooth borechamber 21 into which inlet 16 opens at an acute angle to the axisthereof. Nozzle member 19 is threadedly attached to barrel member 18.The bore of nozzle member 19 is flared inwardly from a point ofattachment to member 18 so as to provide a conical valve seat 22 openinginto orifice 23. Nozzle member 19 also is provided with a discharge tip24.

A rod type closure member 25 is mounted along the internal axis ofbarrel member 18 in position to cooperate with conical seat 22 andprovide a valve controlling flow through orifice 23.

It is an essential feature of the invention that TEE included angle ofconical valve seat 22 be not more than about 28. Preferably, theincluded angle is as small as feasible and less than 24. In operation,it is desirable that the cross sectional clearance area within theconical valve opening should be at least that of the nozzle orifice whenthe valve is in the open position.

In the design of the applicator gun, it is desirable to have thediameter of inlet 16 equal to that of delivery tube 114 and to have eachtubular member smoothly aligned. In the internal design of barrel member18 it is important that the cross sectional area of bore 21, excludingthat of rod valve closure member 25, shall approximate at least 4 timesthat of the cross sectional area of inlet tube 16. In this way smoothoperation in rapid production work is facilitated since the excesscapacity of the gun barrel compared to that of the de livery tube actsas a plenum chamber. A variety of known valve actuating mechanisms canbe employed to actuate the rod valve of applicator gun 15. For ex ample,the valve can be pneumatically or hydraulically 3 operated for automatichigh speed operation, or it can be controlled by the electric solenoidlifting mechanism. In the example of the drawing, a simplified handoperated system is illustrated. The valve actuating member is fitted tobarrel member 18 by means of threaded connector 26. A collar or collet27 on the upper portion of rod member acts as a stop in conjunction withshoulder 28. Rod valve member closure is held in the closed position bythe tension of a spring 29 surrounding the stem 30 against collet 27 andthence against shoulder 28. Hand lever 31 is mounted above the springhousing 32 on member 20 by pins 33 and 34. When pressure is applied tohand lever 31, rod 35 is moved in a direction forcing valve collet 27 bypressure from shoulder 28 against spring 29, thereby drawing rod closuremember 25 clear of the nozzle conical seat 22 and nozzle orifice 23.

The position of rod closure '25 in the retracted or open position isshown in FIGURE 2. The structure of the rod closure 25 is better shownin FIGURE 3, illustrating the advantageous use of a plastic tip 36 whichmay be screwed on the end of stainless steel rod 25. It has been foundin the practice of the invention that the use of a plastic tip for therod closure member provides substantial advantages. As indicated inFIGURES 4, 5 and 6, the plastic tip combines a scraping action (FIG. 5)as the valve begins to close with a wiping or squeegee action (FIG. 6)as the rod closure reaches full extension. The plastic tip may beconstructed of any high melting plastic material, e.g. nylon,polyethylene, Teflon, Buna S or N, synthetic rubber, etc. Advantageouslythe material should be resistant to oils and hydrochloric acid, orotherchemicals which may be encountered in handling the pastes. Compared tothe use of a metal tip, the plastic tip provides a valuable wiping orsqueegee action which adds considerably to the operational life or thenozzle with soft solders. The metal to metal contact which results fromthe use of an all metal rod tends to build up a ridge of metal on thevalve seat caused by plating out of metal from the solder, particularlyin the case of soft solders, by the hammering action of the valveclosure although metal to metal valve closure contact may be better withthe hard solders.

In the operation of the applicator gun, supply tank 110 is filled withthe appropriate paste, and then air pressure is applied to the surfaceof the paste in tank 110 forcing paste to flow through delivery tube 114and inlet 116 into bore 21 of applicator gun 15. The pressure requiredwill vary considerably depending upon the type of paste, the dimensionalrelationships of the equipment, and the particular applicator required.For example, in dotting with soft solder pastes, pressures as low asl0l2 p.s.i.g. may be sufficient. However, a pressure of about 25-35 lbs.is recommended with paste solders, about 40 lbs. with copper brazepastes, and about 60 lbs. with silicone greases. The nozzle orificeopening can be varied within considerable limits to meet therequirements of particular paste and service. With an orifice opening of0.0550 inch, I have operated applicator guns of the invention for over300,000 cycles without shut down for cleaning or repair. The valve rodscomprised /s-in. diameter stainless steel rods with Buna S and Teflontips, and the included angle of the valve seat surrounding the nozzleorifice was 22". With the same equipment but using an included angle of24, trouble free operation extended to 85,000 cycles, while with a 28angle, it was diificult to obtain as many as 25,000 cycles. When theincluded angle was increased to as much as 30, the system becameinoperable; the valve closure was inadequate, bad wear resulted andridges of plated out paste quickly built up on the valve seat.

A variety of nozzles of different designs for different types of pasteapplication can be used with my invention. FIGURE 7 illustrates a shortnozzle which is designed as a high velocity, squirt type nozzle,operating 4 at about 60-70 p.s.i.g. FIGURE 8 illustrates an elongatedtip nozzle which can be used for dotting or striping and which permitsaccess to small or restricted openings. This type nozzle works with softsolder pastes at pressures as low as 8 to 40 p.s.i.g.

In FIGURES 9 and 10, a nozzle assembly is illustrated which includesnozzle member 40 containing orifice 41 within threaded tip 42. which isadapted to engage with corresponding threads 43 in nozzle adaptor 44.Nozzle adaptor 44 is flared outwardly to provide an enlarged dischargeoutlet which can be fitted with nozzles of special design; e.g. thescreen nozzle 45, illustrated in plan view in FIGURE 12, and in sectionin FIGURE 11. This wire mesh nozzle can be used in a flexible manner toapply selected designs on a surface with a solder or paste. Anotherspecial nozzle outlet which can be fitted to the applicator gun by meansof the adaptor assembly of FIGURES 9 and 10 is shown in FIGURES 13 and14 which illustrate respectively in plan view and vertical section amulti-dot orifice 46 which is equipped with a plurality of elongatedsmall diameter nozzle tips 47.

As has been described above, the applicator gun of the inventionprovides substantial advantages in production line soldering orapplication of other industrial pastes. It is capable of considerablevariation in design and can be flexibly adapted to a variety of uses. Itis advantageously operated by air pressure but other hydraulicpressuring means can be used as known in the art.

I claim:

l. A pressure type applicator gun which comprises a smooth bore barrelcontaining an inlet port at one end thereof, an outlet port at the otherend of said barrel defining a discharge orifice of cylindrical crosssection, a conical faced valve seat opening from the bore of said barrelinto said port wherein said valve seat is defined by a cone having asection an included angle of not more than 28, a rod type cylindricalvalve closure member having a plastic tip comprising a high meltingpolymeric plastic material and having a greater cross sectional area atits tip than that of said outlet port, and means for actuating said rodclosure member, whereby the valve closure member and seat arecharacterized in closing by the plastic tip of the closure memberseating above the outlet port in end edge to conical surface contactwith the internal face of the conical valve seat thereby effecting awiping squeegee action on said internal face, and in opening by a crosssectional clearance area of the conical valve opening of at least thatof the outlet port.

2. The applicator gun of claim 1 wherein the included angle of theconical valve seat is about 18 to 22 degrees.

3. The applicator gun of claim 1 which comprises as separate members thebarrel and a discharge nozzle section containing said outlet port andconical faced valve seat, and wherein the internal cross sectional areaof the barrel exclusive of the valve closure member is at least fourtimes that of the inlet port.

4. A pressure type applicator for solder pastes which comprises incombination a supply tank having a cone-bottom with central outletwhereof the included angle of the cone is about 20 to 36 degrees, meansfor applying pressure to material in said tank, an applicator guncomprising a smooth bore barrel containing an inlet port at one endwherein the internal cross sectional area of the barrel (exclusive of avalve closure member hereinafter defined) is at least four times that ofthe inlet port, a delivery tube of equivalent cross section to that ofsaid inlet port connecting the outlet of the tank with the inlet port ofthe barrel, an outlet port at the other end of said barrel defining adischarge orifice of cylindrical cross section, a conical faced valveseat opening from the bore of said barrel into said port wherein saidvalve seat is defined by a cone having in section an included angle ofnot more than 28, a rod type cylindrical valve closure member having aplastic tip comprising a high melting polymeric plastic material andhaving a greater cross sectional area at its tip than that of saidoutlet port, and means for actuating said rod closure member, wherebythe valve closure member and seat are characterized in closing by theplastic tip of the closure member seating above the outlet port in endedge to conical surface contact with the internal face of the conicalvalve seat thereby elfecting a wiping squeegee action on said internalface, and in opening by a cross sectional clearance area of the conicalvalve opening of at least 150% that of the outlet port.

References Cited in the file of this patent UNITED STATES PATENTS1,004,794 Keeton Oct. 3, 1911 6 Wolfe Dec. 30, 1919 Clizbe et al Ian.18, 1938 Brarnsen et al. Apr. 2, 1940 Ekstrom Oct. 29, 1940 Bashore Oct.9, 1951 Tucci July 21, 1953 Pyles Feb. 23, 1954 FOREIGN PATENTS CanadaJan. 7, 1952 France Apr. 16, 1932

